Process of and apparatus for air



PROCESS OF AND APPARATUS FOR AIR CONDITIONING Filed Jan. 11, 1932 2Sheets-Sheet 1 INVEN TOR.

A TTORNEYS Sept. 15, 1936.

PROCESS. OF AND APPARATUS FOR AIR CONDITIONING Filed Jan. 11, 1932 2Sheefcs-Sheet 2 INVENTOR.

BY Mi #W swa A TTORNE Y.

J. N. HADJISKY 2,054,158

Patented Sept. 15, 1936 UNITED STATES PROCESS OF AND APPARATUS FOR AIRCONDITIONING Joseph N. Hadjisky, Birmingham, Mich.

Application January 11, 1932, Serial No. 585,918

29 Claims.

This invention relates to air conditioning apparatus, and moreparticularly to an improved process for controlling the temperature andhumidity of the air within a given space, by providing positive meansfor circulating such air, and

means appurtenant the circulating apparatus for conditioning the air socirculated. Various systems and constructions have been employed in thepast for accomplishing this purpose, which systems, however, have hadmany inherent limitations, and have been so cumbersome and complicatedas to prohibit their use in private homes, and to confine their use toauditoriums, large buildings, theaters, etc.

15 The system perhaps most commonly used incorporates positive aircirculating means in connection with which a given portion of the airdesired to be conditioned is treated in a single chamber, in whichit isboth cooled and dehumidi- 20 fied.

is of course dependent upon accurate control of the temperature of thecooling medium, (usually cold water spray or combined spray andrefrigeration). The only other system in common use 25 for accomplishingsimilar results provides a separate dehydrating chamber, in which isplaced a moisture absorptive substance (frequently silica gel or thelike) for removing moisture from the air, while the cooling is entirelyperformed in a separate and usually second chamber incorporatingrefrigeration or cooled water coils, cold water spray or the like. Thisarrangement is necessarily even more elaborate than the system firstmentioned, as two complete and separate de- 5 humidifying systems mustbe provided, together with means for driving the moisture from one whilethe other is working. Moreover, both these arrangements not onlynecessitate use of apparatus occupying more space than is available inthe 40 ordinary home, but the close regulation of the temperature of thecooling medium, etc., necessary to be maintained, obliges the attendanceof an engineer practically constantly, further adding to the expense andimpracticality of installations of such types in places where economy orspace must be considered.

My improved process contemplates use of separate chambers for coolingand dehumidifying, the functions of which are interlocked and over- 50lapping in operation, although they are controlled by independenthumidity and temperature-responsive regulating means, or theirequivalents. Both the temperature and humidity of the conditioned airdischarged by such apparatus, when In such a system the conditioningprocess.

operated in accordance with the principles of my improved process, arerelatively independent of variations of temperature of the cooling mediain each chamber. The last statement requires the further explanatoryobservation that I preferably employ cooling coils for dehumidifying aswell as 5 cooling. This latter feature assists in enabling incorporationof the process in apparatus of novel simplicity and compactness.

In order to illustrate the principles of my invention I have shown twoconstructions in which 10 the same are incorporated, but in which forpurposes of clarity I have conformed, insofar as possible, to standardpractice in the construction of air conditioning apparatus, varyingtherefrom only to the extent required to incorporate the principles ofmy invention. The invention, however, insofar as the process isconcerned will be seen to be entirely independent of the apparatus used.

From the foregoing brief rsum of the problems and conditions existing inthe field here involved, it is believed that the primary objects andadvantages of my invention may easily be gathered.

They may briefly be stated to be the provision of a new system of airconditioning utilizing apparatus much simpler both in construction andoperation than it has hitherto been possible to use.

A further object of my invention is the creation of a novel degree offlexibility of operation in the conditioning process by controlling thedegree of dehumidification and also the cooling process by varying thepercentage of air treated in each chamber, independently of temperaturevariations of the cooling agent. Such arrangement allowing thetemperature of the cooling and dehumidifying agents to vary through aconsiderable range, creates important and valuable advantages which willbecome more apparent as the description progresses. The ability tocontrol separately and independently the temperature and the humidity ofthe zone served irrespective of temperature fluctuations of the coolingagent, enables achievement of flexibility heretofore altogetherimpossible.

A further object of my invention is the provision of a system, sosimple. that it may be incorporated in practical apparatus of very smallsize and low price, for home use or other uses where attendance of anoperating engineer is not desirable.

A further object of my invention is the provision of such animproved'process, utilizable in conjunction with a supply of coolingwater which may be at a temperature only slightly below that desired forthe conditioned air, thus frequently enabling use of a city or deep wellwater supply,

for example, without necessitating artificial cooling thereof.

Other objects and advantages will be apparent from the followingdescription, wherein reference is made to the accompanying drawingsillustrating preferred embodiments of my invention, and wherein similarreference numerals designate similar parts throughout the several views.

In the drawings:

Figure 1 is an isometric view of the exterior of one form of suitableapparatus embodying the principles of my invention;

Figure 2 is a vertical sectional view thereof taken substantially on theline 22 of Figure 1 and looking in the direction of the arrows;

Figure 3 is a vertical sectional view taken substantially at rightangles to Figure 2 and on the line 33 thereof, looking in the directionof the arrows;

Figure 4 is a plan view in partly horizontal section taken substantiallyon the plane 44 of Figure 5 and looking in the direction of the arrows,showing a somewhat modified form of my invention, and

Figure 5 is a vertical sectional view thereof taken substantially on theline 55 of Figure 4, and looking in the direction of the arrows.

In carrying out my improved process I provide separate chambers forcooling and dehumidifying, in each of which a cooling agent is employed.In most air conditioning systems, as above stated, a single chamber isused for both cooling and dehumidifying. Since dehumidification of suchair as is usually desired to be conditioned cannot ordinarily beefiected at any but relatively very low temperatures, usually requiring,if temperature difference is to be employed for dehumidification, atemperature of about to 60 F. in the dehumidifying chamber, it followsthat if this same chamber is used for cooling as well, a wastage ofrefrigerating facilities results, from the necessity of reducing theentire chamber to the extremely low temperature required to accomplishdehumidification, whereas the cooling could just as well be done at atemperature difference of only a few degrees. By separating the coolingand dehumidifying processes to as great an extent as is possible, whileyet using cooling media for both purposes, and by a novel system ofcontrol, I attain the above outlined results.

First considering the specific apparatus shown in Figures 1, 2 and 3,after a description of which the process itself may be more readilyunderstood: Reference character I designates the casing of one form ofillustrative apparatus, which may, as shown, be embodied in a singlehousing. Air inlets 22' are provided in and adjacent the bottom portionsof its walls, one of which may, if desired be for re-circulated and theother for fresh air. As shown in Figure 2, the entering air is dividedinto three portions by partitions 55' which divide the interior of thehousing directly above the inlet chamber 3 into three sections, 6, 'Iand 8.

The first of these (6) is a by-pass passage, through which air may beallowed to flow, untreated, directly to the circulating fans, by whichit is forced from the outlet. The by-pass is so arranged as to alwaysallow the flowing therethrough f a quantity of air sufiicient to providea controlling balance which in regulated cooperation with the humidifiedand cooled air, the quantity of which is subject to continuous control,

chamberis smaller than the cooling chamber,

and the air travel through it normally less, a relatively smallrefrigerating unit answers, although the coil 9 is best maintained at arelatively low temperature. While the coil 9 serves to somewhat lowerthe temperature of the air flowing through the compartment 8, itsprincipal function is that of dehumidifying such air. Air passingthrough this compartment is further dried by the water droplet arresterII, comprising a series of spaced'substantially par llel crenelatedvanes through which the air must pass and upon which any globules ofmoisture it may contain will be caught.

A relatively greater percentage of the total air flow through theconditioner is ordinarily passed through the larger cooling chamber I,where the coils I0, which may be at a considerably higher temperaturethan the dehumidifying coils, perform a major portion of the coolingoperation. The pipe lines leading to the cooling chamber may be runthrough the dehumidifying chamber to pre-cool the air entering thelatter, or as shown in Figure 2, a portion of the tubes themselves maybe run through the dehumidifying chamber.

These dehumidifying pre-cooling portionsof the tubes are designated III.

A series of dampers I2-I3 extends across the housing in such manner asto control the entire air flow therethrough. The dampers I2 are arrangedto control the flow of the air which has passed through the by-pass andcooling chambers 6-1, which air may mingle in the space 2| above thembefore flowing through the dampers. The dampers I3, which control theair flow through the dehumidifying chamber 8, may as shown be connectedto and controlled together with the same mechanism as the dampers I2,being so arranged that as the dampers I2 are moved toward closed thedampers I3 are moved toward opened position, and vice versa. A lostmotion connection is provided, or variant damper construction utilized,so arranged that when the dampers I3 are completely open, the dampers I2are only partially closed. The details of the mechanism are of courseimmaterial inasmuch as my invention concerns primarily the processinvolved. The air which has passed through the dampers into the chamberI4 may beforced from the outlet I8 by the fans I5, driven by an electricmotor I6. The desired cooling of the coils I0 may be accomplished bycold water alone. The inlet and outlet couplings for this coil may alsobe mounted upon the exterior of the casing, as indicated at I0".

The damper 4 controlling the by-pass passage may be directly controlledin response to the temperature changes in the area whose atmosphere isbeing conditioned, by means of a thermostat (not shown) directlyconnected to a bellows-operated or other suitable actuating mechanism I9arranged to open the damper in response to a fall of temperature, andclose it upon a rise of temperature, to force a greater percentage ofthe airto pass through the cooling chamber.

The dampers l2--|3 may be controlled by a hygrostat (not shown) alsolocated in the zone whose atmosphere is to be conditioned, and similaractuating mechanism 20 arranged to be responsive thereto. These dampersare so adjusted that upon a fall of humidity the dampers l3 tend toclose and the dampers I2 to open, so that a smaller percentage of theair passes through the dehumidifying chamber 8 and a greater percentagethrough the sections 6, I, and vice versa.

It will be seen that by virtue of the automatic control of the dampers4-l2-l3 thus provided, the percentage of air by-passed, and that at anytime passing through the cooling. and dehumidifying sections, isconstantly subjected to, positive control which is entirely independentof the temperature of the coils 9-40, and responsive only to conditionsin the area served. Thus if the temperature in the served area tends tofall too low, the by-pass damper 4 is automatically opened, and agreater quantityof untreated air allowed to flow therethrough, whilevariances in the humidity of the air in the controlled zone are alsoautomatically compensated for by the dampers l2|3. A drip pan, as 3' maybe employed and positioned, as shown in Figure 2, beneath the coils, tocatch any condensed moisture which may fall therefrom. A drain pipe 3"is also shown, although these features are ot course immaterial insofaras the invention is concerned.

This method of incorporating dehumidifying, cooling and by-pass passagesentirely in one casing, and of varying. in response to continuousautomatic control the percentage of the total air flow which ispermitted to pass through each chamber, in response to conditions in theserved area entirely, and independently of the temperature of thecooling and dehumidifying agents used in the apparatus, may be embodiedin apparatus of various forms. The performance of my improved system isfurther largely dependent upon the constant flow of at least some airthrough the by-pass, so that by direct and controlled variation of suchflow independently of the remainder of the apparatus, the temperature ofthe controlled air may be subjected to constant and simple control. Manyvariant but suitable forms of apparatus will doubtless suggestthemselves to those skilled in the art.

A more detailed study of the efiect upon the dehumidification andcooling processes of variations in temperature of the dehumidifying andcooling media, and an analysis of the total heat content balance as itis divided between the two chambers, will show both the independence ofthe systems operation with respect to such variations, its flexibility,and the casualrelation between the scientific control of the variablesand the mathematical laws behind the process and the results which theprocess achieves.

An illustrative case will be considered to show the quantitativeanalysis of the passage of air through such an arrangement of apparatusas has been described in connection with Figures 1, 2 and 3. Thecalculations are made on the basis of one pound of air as the unitamount handled 'and passed through the system. The

heat and moisture loads are typical of a residence.

air conditioning problem. The given conditions are as follows:

1. Temperature of air in inlet chamher 3 82 F. 2. Moisture content perpound or air in chamber 1 66 grains 3. Total heat per pound in air inchamber 3 29.6 B. t. u.

4. Heat load to be removed per pound I of air in chamber 3 3.3 B. t. u.5. Moisture load to be removed per a pound of air in chamber 3 3.9grains We will further assume the following required conditions:

1. Final moisture content per pound of air at outlet (ll) 62.1 grains 2.Total heat in air per pound delivered at outlet L 26.8 B. t. u. 3. Finaltemperature of air leaving outlet (approx) '70.5F.

In the tabulated cases below I shall assume three different temperatureconditions in the dehumiditying chamber, the temperature in the coolingchamber being assumed to remain constant. The weight of the air thatwillpass through the dehumidiflcation process can be found from theequation:

Di -M W Pounds wherein Wx=weight of air passing through dehumidifyingchamber per pound of air delivered to entire system. Mx moisture load tobe removed per pound 0! air (given) =3.9 grains,

Ma moisture content per pound of suppliedair (given) =66 grains.

Md=moisture content per pound of air leavin dehumidifying chamber. Seetabulated values below for each case. Substituting in the equation, thefollowing results are obtained:

A study of these calculations discloses the fact that a random variationof temperature of the cooling agent of from 10 to 13 F. does not in anymanner interfere with the dehumidifying process or its control. Therelatively small proportion of the total treated air passing through thedehumidifying chamber (Wx) is shown by Item 6. Item 8 shows therelatively slight in crease in the amount of air necessary to be passedthrough the dehumidlfying chamber per degree rise in temperature.Comparison oi. thevalues shown in Items 4 and 5 makes plainthe fact thatit would require an abnormal increase in the value Mx'to greatly affectin proportion to the volume of air treated, i. e., the value Item 6 Inpractice, such abnormal changes in the mois-' ture load as those herecontemplated do not occur. Thevariation of moisture load, expressed ingrains per pound of air is ordinarily very gradual and slight from hourto hour.

Considering Item 6 from a somewhat difl'erent angle it will be seen thatits maximum increase relatively to the whole pound of air handled is 14per cent, but its absolute increase from case 3 to case I is I make useof this relationship to control the process in the dehumidif yingchamber, and the relatively large absolute variation" of the amount ofair to be passed through the chamber makes possible the use of a damperto control the same, with-the resultant simple and reliable operationcharacteristic of this means of com trol, especially where velocities,as here, are low. The process is thus regulated by the value Wx, whileWx in turn is controlled by a damper (l3) responsive only to thevariation of Mx in the served area; throughout wide variances in thetemperature of the cooling agent.

Considering next the balance of the total heat content as it is dividedbetween the cooling and deh umidifying chambers, it should be noted thatsome heat is removed from the air in the dehumidifying chamber without acorresponding fall of temperature, in accordance with a well known lawof thermodynamics.- The relative quantity of air passing through thedehumidifying chamber is ordinarily less than through the coolingchamber, as above stated. A temperature drop is of course caused by theremoval of heat from the air in this chamber, which heat is removed bycondensation of moisture in the air. and some by cooling of the airitself. The total heat removed may be expressed by the equation,

Tabulating and calculating yalues for heat balance duringdehumidification process in the three assumed cases:

Tabulation of calculated values for heat balance duringdehumidz'flcation process Cases Dehumidifier chamber temperatures,

degrees F Wx (from previous tables) in pounds... Hzgatt load to beremoved (given) u H; (given) F4 (from standard tables)- H:H H,=Wx(IIJIIJ)=B. t. u Per cent of heat load removed 6 Percent of heat loadleft to be removed by cooling process 34.

Thus it is seen that in these assumed cases from to per cent of thetotal heat load is removed by the dehumidifying chamber of theapparatus.

The exact percentage of heat which will be removed by the dehumidifierchamber is proportional to the relation of the sensible heat load to thelatent heat load. This, however, is established by the conditions ofeach problem and cannot be changed very much. It is of course desirableto remove in the dehumidifying chamber as small a percentage of thetotal heat load as possible.

Examining the equation H:=W:(H3Ha), the

, next important factor, Wx, is also seen to be fixed by the moistureload. The only variables which can be utilized for the purpose ofabsorbing more of the heat with the coils i0 is to decrease H3 in theequation Hx=W:(H'3-Hd) or to increase Ha. But as I have chosen to allowa random fluctuation of the temperature of the cooling medium in coils 9from 35 to 48 F. for special purposes, H; is the logical and mosteffective item to be changed in its relation to the dehumidificationchamber process. The means I have chosen to do this are the following:By extending part of coil ID in chamber 1 through the lower part ofchamber 8 the air going into the chamber 8 is pre-cooled. It can beshown by calculation that in this way an amount of heat load from 12 to30% of the total can be added to the cooling chamber coils- Cases 1 23 1. Total heat load (given) 13. t. u 3.3 3.3 3.3 2. Heat load removedby dehumidifier... 2. 17 l. 97 1.81 3. Remaining heat load to be removedby cooling process l. 13 1. 33' 1.49 4. Maximum weight 0! air capableoipassing through cooling chamber per pound circulated 756 850 892 5.Temperature of air in chamber 3, given,

degrees F 82 82 82 6. Temperature drop it all air in Item 4 is coo 6. 36. 6 7.05 7. Temperature drop of such air is cooled 8. 4 8. 9. 36 8.Temperature of air leaving cooler ii 75% goes through, degrees F 73v 673. 15 72. 64' 9. Temperature of air leaving cooler ii 50% goes through,degrees F 71. 5 71 70 Items 6 and 7 show the relatively smalltemperature drop required to perform the cooling operation. The secondresult of importance will be noted from a study of Items 8 and 9.Comparing the final temperature here with the final temperature in thedehumidifying chamber it will be seen that there is a difference ofabout 30 F. The cooling process can thus be carried on with a coolingagent at a much higher temperature than is required in thedehlimidifying chamber. This temperature difference will be seen torepresent pure gain insofar as economy of operation is concerned, sinceit is unnecessary to provide refrigerating means at the relativelygreatly re- '.duced temperature used in the dehumidifying chamber. Inthe cooling chamber it is usually possible to employ city water as thecooling medium rather than artificial refrigeration; at, of course, aconsiderable saving of expense, since such cooling water is used toremove about half the entire heat load, whereas in the processesheretofore used it has been necessary to use artificially cooled meansfor. removing the entire heat load. Even if artificial refrigeration isalso used to reduce the temperature of the cooling chamber, aconsiderable saving in expense of operation results from the employmentof my improved process, since carrying this chamber at a relatively hightemperature (perhaps 60 F.)

permits employing more economical and compact refrigerating apparatus.Perfect results can also be obtained by the use of ice cooled water inthe dehumidifying chamber and city water for the cooler, thus dispensingwith artificial refrigeration entirely.

A consideration of Items 4, 6 and '7 shows that there may beconsiderable variation in the amount of air passing through the coolingchamber. I make-use of this fact to further control the process bycontrolling this factor, rather than controlling the temperature of thecooling agent as is the common practice.

Another suitable arrangement of apparatus for carrying out my improvedprocess is shown in Figures 4 and 5, in which is shown a constructionwhereby the air is first permitted to flow through the by-pass andcooling chambers, after which a regulatable and variable portion of theentire flow passes through the dehumidifying chamber I08. In thisconstruction, in which analogous parts to those described in connectionwith the first mechanical embodiment have been given similar referencenumerals one hundred integers higher, the dampers |2| I3 may besimilarly controllable and reversibly operable, under the influence ofthe humidity-responsive actuating member I20. Similar lost motionconnection between the dampers is also preferably provided. The by-passdampers I04 are connected to the temperature-responsive controllingmember H9,

and thus regulate the percentage of air which is forced to pass throughthe cooling chamber I01. Separate refrigerating units l22l23 may be usedfor cooling the coils l09'l l 0, with the benefits of economy previouslyoutlined resulting from the elimination of the necessity of performingthe cooling by means of coils maintained at low temperature or ifdesired, cold water spray may be utilized in the dehumidifying chamber,as shown in Figures 4 and 5. In these views the nozzle-carrying spraypipes are designated I 09, the coupling means for connecting the coldwater lines thereto, I09. Whatever the cooling agent utilized in thedehumidifying chamber, the more greatly reduced temperature need bemaintained only therein, while the cooling chamber may be operated atthe higher temperature made possible by'my improved process, thusobtaining the above outlined inherent economies.

While it will be apparent that the illustrated embodiments of myinvention herein disclosed are well calculated to adequately fulfill theobjects and advantages primarily set forth, it is to be understood thatthe invention is susceptible to variation, modification and changewithin the spirit and scope of the subjoined claims.

What I claim is:

1. In an air conditioning apparatus, separate chambers through which airto be conditioned is tion is the paramount consideration, and in anotherof which temperature correction is intende ed to be effected, and meansfor controlling the functioning of the apparatus, comprising interlockeddamper means for controlling the flow through each such chamber, soarranged that by continuous movement such damper means may be made toeffect opening movement of one and closing movement of the other.

2. In an air conditioning apparatus, separate chambers through which airis adapted to flow, in one of which humidity correction is the primaryconsideration, in another of which principally tcmperature correction iseffected, and through another of which untreated air may pass, and meansfor controlling the functioning of the apparatus, comprisinghumidity-responsive damper means for interdependent controlling of theproportion of treated air passed through the dehumidifying chamber andthat passed through the remaining portions of the apparatus, one beingadapted to be moved toward opened and the other toward closed positionby continuing movement of said damper means, and additional dampermeans, responsive only to the temperature'in the served area, forcontrolling the proportion of air by-passed.

3. In an air conditioning apparatus incorporating separate chambers, acooling coil within one chamber adapted primarily for cooling, a secondcooling coil at a relatively lower temperature than the first, arrangedwithin another chamber and primarily intended for dehumidification, aportion connected to the first mentioned coil being extended through thesecond chamber in a manner adapted to pre-cool the air passingtherethrough.

4. The process of cooling and dehumidifying air which includescirculating the air desired to be conditioned, dividing the air socirculated, changing the humidity'of one such divided portion,concurrently separately changing the temperature of another dividedportion of the air, concurrently by-passing another divided portion,varying the proportion of the air passed thru the humidity-changingmedium in response to humidity conditions in the conditioned zone,varying the volumetric proportioning of air between i the by-Dass andthe temperature controlling medium in response to thermal conditions inthe served zone, and recombining the portions of air so treated.

5. The process of cooling and dehumidifying air which includescirculating the air desired to be conditioned, dividing into separateportions the air so circulated, concurrently varying the humidity of onesuch divided portion and the temperature 'of another, controlling theair flow thru the humidity varying section in response to humidityconditions in the conditioned zone, concurrently by-passing anotherportion of the air around the temperature corrective section and?separately controlling the air flow thru the bypass in response totemperature conditions in the conditioned zone.

6. The process of cooling and dehumidifying air which includescirculating air from and to the area desired to be conditioned, dividinginto separate portions the air so circulated, varying the humidity ofone such divided portion in the desired direction by 'absorbing heattherefrom, concurrently separately varying the temperature of anothersuch divided portion in the desired direction, so controlling theproportion of the total air flow thru the humidity varying section inresponse to humidity conditions in the served zone and the proportion ofthe total air flow thru the temperature varying section in response totemperature conditions in the served zone as to provide correctiveadustment of the humidity and temperature of the conditioned airrelatively independently of reasonable temperature variations of thecorrective agencies.

'7. The process of cooling and dehumidifying air which includescirculating air from and to the area whose air is desired to beconditioned, dividing into separate portions the air so circulated,varying the humidity of one such divided portion, concurrentlyseparately varying the temperature of another such divided portion,varyingly apportioning the quantity of air passing thru each in responseto humidity and temperature conditions respectively in the served zone,concurrently permitting another divided portion of the air stream topass untreated, and controlling the volumetric portion of thecirculating air so by-passed also in response to temperature variationsin the served zone.

8. The process of cooling and dehumidifying air which includesmaintaining a refrigerating agency for temperature correction at atempera ture below that of the air to be conditioned, maintaining ahumidity corrective agency at a relatively lower temperature,concurrently causing circulation of separate air streams through eachsuch agency, and controllingly apportioning the quantity of airpermitted to flow thru each in response to temperature and humidity.conditions in the area whose air is desired to be conditioned.

9. In air cooling and dehumidifying apparatus, a cooling agency at alower temperature than the air desired to be cooled, thru which such airmay circulate, a dehumidii'ying agency at a more greatly reducedtemperature and thru which air may be passed, damper means forcontrolling the volume of air passing thru each agency, means for socontrolling the damper in response to humidity variations in the servedzone as to maintain one agency open to the passage of air whilerestricting the other, and vice versa, a by-pass around the temperaturecorrective agency, and means for controlling the air fiow thru thebypass in response to variations of temperature in r the served zone.

10. In an air cooling and dehumidifying system having an inlet and anoutlet, an air cooling agency at a reduced temperature relatively to theair to betreated, a dehumidifying agency at a. lower temperature, meansfor conducting air over each agency, a portion of the cooling agencybeing placed in advance of the dehumidifying agency so that air passesthru them in the order named and is pre-cooled by'the cooling agencybefore entering the dehumidifying agency, a bypass for conducting airfrom the inlet to the outlet without passing it through either agency,temperature responsive controlling means for the by-pass, and humidityresponsive controlling means whereby the fiow through the dehumidifyingagency may be regulated.

11. The process of conditioning air which includes providing a coolingagency at a reduced temperature, and a dehumidifying agency at a lowertemperature, and passing a portion of the air to be treated thru eachand a portion thru neither, but passing the air supplied to the de-'humidifying agency first thru the cooling agency to be there pre-cooled,and regulating the air by-passed and passed through each agency inresponse to changes in temperature and humidity in a served zone.

12. The process of conditioning air which in cludes providing a coolingagency at a reduced temperature, and a dehumidifying agency at a.reduced temperature and a dehumidifying agency at a lower temperature,passing a portion of the air thru the cooling section, by-passing aportion therearound, and passing part of the pre-cooled air thru thedehumidifying agency, and controlling the proportion of air by-passedand passed through said agencies in response to temperature and humidityconditions in a served zone.

13. The process of cooling and dehumidifying air which includes formingthe air to be conditioned into a flowing stream, passing a portion ofthe stream through a temperature corrective medium operating bytemperature differential, passing another portion of the stream througha humidity corrective medium which also acts by temperaturedifferential, and delivering the stream portions so treated to a servedzone.

14. The process of cooling and dehumidifying' air which includes formingthe air to be conditioned into a flowing stream, passing a portion ofthe stream through a temperature corrective medium acting by temperaturedifferential and which is held at a temperature below that of the itycorrective medium held at a still lower tem-- perature, and deliveringthe stream portions so treated to a served zone.

15. The process of cooling and dehumidifying air which includes formingthe air to be conditioned into a flowing stream, passing a portion ofthe stream through a temperature corrective agency at'a temperaturebelow that of the air to be conditioned, passing a portion of saidstream through a humidity corrective agency acting by temperaturedifferential and held at a lower temperature than said first mentionedagency, controllingly varying the percentage of the total air fiowpassed through each agency, and delivering the stream portions sotreated to a served zone.

16. The process of cooling and dehumidifying air which includes formingthe air to be conditioned into a flowing stream, passing a portion ofthe stream through a temperature corrective agency at a temperaturebelow that of the air to be conditioned, passing aportion of said streamthrough a humidity corrective agency acting by temperature differentialand held at a lower temperature than said first mentioned agency,bypassing a portion of the air untreated past both agencies, andcontrollingly apportioning the quantities of air by-passed and permittedto flow through each agency.

17. The process of cooling and dehumidifying air which includes formingthe air to be conditioned into a flowing stream, passing aportion of thestream through a temperature corrective agency at a temperature belowthat of the air to be conditioned, passing a portion of said streamthrough a humidity corrective agency acting by temperature differentialand held at a lower temperature than said first mentioned agency,by-passing a portion of the air untreated past both agencies,controllingly apportioning the proportion of air by-passed in responseto. temperature conditions in the served area, and similarly controllingthe proportion of flow through each of said agencies in response tohygrostatic conditions in said area.

18. The process of dehumidifying air which comprises maintaining arefrigerating agency at a reduced temperature, and varying the quantityof air permitted to pass therethrough in accordance with the equation19. The process of cooling and dehumidifying air which includesmaintaining two separate refrigerating media at reduced temperatures butone at a lower temperature than the other, passing air desired to bedehumidifled through said lower temperatured medium, passing air desiredto be cooled but not dehumidified through the other medium, controllingthe proportion of the air passed through, the dehumidifying medium inresponse to changes of humidity in a served zone, and controlling theproportion of air passed through the cooling medium in accordance with aquantity of heat remaining to be removed, considering the proportionalquantity .thereof removed by the dehumidifying medium.

20. The process of conditioning air which includes maintaining separatecooling and dehumidifying media at reduced temperatures with respect tothe air desired to be conditioned, but holding the dehumidifying mediumat a lower temperature than the cooling medium, circulating such airthrough both media, and controlling the apportionment of the" airallowed to flow through the cooling medium in accordance with the percentage of heat remaining unremoved by the dehumidifying medium, asexpressed by the equatiOD H:=W:(H3-Hd).

21. The process of cooling and dehumidifying air which includesmaintaining a refrigerating agency for temperature correction at atemperature below that of the air to be conditioned, maintaining anotherrefrigerating agency for humidity correction at a still lowertemperature, causing circulation of air through each of said agencies,by-passing another portion of air untreated, con.- trollingly varyingthe aiiflow through the humidity corrective agency in response tochanges of humidity conditions only, and controllingly varying theby-passed air in response to temperature conditions only.

22. In an air cooling and dehumidifying system having an inlet and anoutlet, an air cooling agency at a reduced temperature relatively to theair to be treated, a dehumidifying agency at a lower temperature, meansfor conducting air over each agency, a portion of the cooling agencybeing placed in advance of. the dehumidifying agency so that air passesthrough them in the order named and is pre-cooled by the cooling agencybefore entering tine dehumidifying agency, and humidity responsivecontrolling means for regulating the flow through both the cooling anddehumidifying agencies.

23. In an air cooling and dehumidifying system having an inlet and anoutlet, an air cooling agency at a reduced temperature relatively to theair to be treated, a dehumidifying agency at a lower temperature, meansfor conducting air over each agency, a portion of the cooling agencybeing placed in advance of the dehumidifying agency so that air passesthrough them in the order named and is pre-cooled by the cooling agencybefore entering the dehumidifying agency, and humidity responsivecontrolling means for regulating airflow within the system.

24. The process of cooling and dehumidifying air which comprises causingair, which is to be conditioned, to circulate in heat exchange relationwith cooling surfaces to remove principally sensible heat from the airwhen the relative humidity of the air to be conditioned is below apredetermined percentage, causing air, which is to be conditioned, tocirculate in heat exchange relation with colder cooling surfaces whenthe relative humidity of the air to be conditioned is above'apredetermined percentage, the temperature of. which colder surfacescauses the air flowing thereover to be cooled to below the dew pointthereof, and controlling the flow of air over the heat exchange surfacesin accordance with the relative humidity of the air to be conditioned.

25. The process of cooling and dehumidifying air which comprises causingair, which is to be conditioned, to circulate in heat exchange relationwith cooling surfaces to remove principally sensible heat from the airwhen the relative humidity of the air to be conditioned is below apredetermined percentage, causing at least a part of such airtocirculate also in heat exchange relation with other cooling surfaceswhen the relative humidity of. the air to be conditioned is above apredetermined percentage, the temperature of which latter surfacescauses the air flowing thereover to be cooled to below the dew pointthereof, and controlling the flow of air over the heat exchange surfacesin accordance withthe.

relative humidity of the air-to be conditioned.

26. An air conditioning system comprising, in combination, a heatabsorber, the main function of which is to remove principally sensibleheat from air flowing thereover, a second heat absorber adapted to coolair flowing thereover to below the dew point thereof, means forcontrolling the flow of. air over the second mentioned heat absorber,and means responsive to the relative humidity of the air to beconditioned for actuating the controlling means.

27. An air conditioning system comprising, in combination, a heatabsorber, the main function of which is to remove principally sensibleheat from air flowing thereover, a second heat absorber adapted to coolat least a part of said air to below the dew point thereof, means forcontrolling the flow of air over the second mentioned heat absorber, andmeans responsive to the relative humidity of the air to be conditionedfor actuating the controlling'means.

28. An air conditioning system comprising, in combination, refrigeratingapparatus including an evaporator, the main function of which is toremove principally sensible heat from air flowing thereover, a secondevaporator adapted to cool air flowing thereover to below the dew pointthereof, means for controlling the flow of air over the second mentionedevaporator, and means responsi've to the relative humidity of the air tobe conditioned for actuating the controlling means.

29. A conditioner unit for air conditioning systems including a pair of.chambers arranged in parallel, one chamber constituting an air coolerfor absorbing latent heat from the air stream passing through it, theother chamber having cooling means therein for absorbing substantiallyonly excess sensible heat of the air passing through it, means fordelivering an air stream to be conditioned to the inlets of saidchambers and for proportioning the amount of the stream which passesthrough the two chambers, means whereby the divided portions of the airstream commingle after leaving the chambers.

JOSEPH N. HADJISKY.

